Files in apt-mirror
The main configuration file is /etc/apt/mirror.list which contains a list of files that you should be aware of in case you have any issues.

/etc/cron.d/apt-mirror

This is the cron configuration template which you can modify. The example which is not active as it is commented out, starts a cron job at 4 AM each day and sends the activity into the log as listed.

Some administrators may want to only update once a week and others will prefer twice a day to be up to date.
#
# Regular cron jobs for the apt-mirror package
#
#0 4 * * * apt-mirror /usr/bin/apt-mirror > /var/spool/apt-mirror/var/cron.log
/var/spool/apt-mirror/mirror

This is the location of the mirrors that you create. Be aware, that the /var directory can fill up and these mirrors will take 15-20 GB each so verify you have the space to set them up.

/var/spool/apt-mirror/skel

The location for the indexes which will list the applications that are available.

/var/spool/apt-mirror/var

The log files, MD5 sums, URLS and clean.sh are placed here as you can see below.